Near Wuda, China, a coal mine revealed some unexpected organic matter. Buried under volcanic ash was a “marvelously preserved” forest some scientists claim could be nearly 300-million-years-old.

Some specimens were preserved “as they fell,” leading scientists at the University of Pennsylvania with Chinese colleagues to create a rather accurate reconstruction of early life in the area.

“It’s like Pompeii: Pompeii gives us deep insight into Roman culture, but it doesn’t say anything about Roman history in and of itself,” U-Penn paleobotanist Hermann Pfefferkorn said in a statement. “But on the other hand, it elucidates the time before and the time after. This finding is similar. It’s a time capsule and therefore it allows us now to interpret what happened before or after much better.”

Here’s more on the research from the university statement:

Due to nearby coal-mining activities unearthing large tracts of rock, the size of the researchers’ study plots is also unusual. They were able to examine a total of 1,000 m2 of the ash layer in three different sites located near one another, an area considered large enough to meaningfully characterize the local paleoecology.

The fact that the coal beds exist is a legacy of the ancient forests, which were peat-depositing tropical forests. The peat beds, pressurized over time, transformed into the coal deposits.

The scientists say they were able to date the ash layer to approximately 298 million years ago. That falls at the beginning of a geologic period called the Permian, during which Earth’s continental plates were still moving toward each other to form the supercontinent Pangea. North America and Europe were fused together, and China existed as two smaller continents. All overlapped the equator and thus had tropical climates.

The researchers believe finding this forest has resulted in several firsts, according to Pfefferkorn: it is the first forest reconstruction for Asia; is the first peat forest found during this time period; and is also the first where Noeggerathiales, an order of now-extinct plants, were seen as the dominant plant group.